A metal filter is an apparatus formed by disposing a porous metal plate made in a plate shape or a tubular shape in a tubular portion through which a fluid flows to filter foreign substances contained in the flowing fluid.
When such a metal filter is continuously applied to a filtering process, foreign substances are attached to and stuck in holes formed in the metal filter and the holes are clogged.
A metal filter for preventing such holes from being clogged is disclosed in Korean Patent Publication No. 10-2006-0037051.
The disclosed metal filter includes a cylindrical shaped support frame having apertures formed on a side surface thereof and a plurality of thin metal plates surrounding the side surface of the support frame and overlapping each other. Further, a plurality of micropores are formed in the thin metal plates, the micropores have minimum diameters at a central position in a thickness direction, and grooves configured to connect the micropores are formed on a surface of the thin metal plate, which is facing the support frame side, and a surface opposite the surface facing the support frame side, thereby improving filtering efficiency.
Further, in the disclosed metal filter, foreign substances stuck in the micropores are removed by a pulse of air which is ejected in an opposite direction with respect to a filtering direction.